I am going to have to turn off ordering this weekend because of my continued illness. I should be able to get it back in operation by the start of the Summer.
If you want one of the modules or a CD_ROM, order now before sales are suspended. Thank you!
A brief infographic about tone controls. The file can be downloaded here.
Looking for a name for your band? I have updated my page of good free band names!
Well, they are free anyway..
Check it out at: http://www.muzique.com/band.htm
Infographic on why pedals pop when switched can be downloaded by clicking on the image above.
Complete article is at https://www.muzique.com/lab/pop.htm
This is a duplicate of the Big Muff but using a quad op amp instead of transistors. The idea of using op amps for the Muff gain stages has been around a long time, and I made my first version of this type of circuit in the late 1990s. About 18 months ago, I got out this old design and updated it and re-sized the board to fit in a 125B enclosure. In fact, I posted a picture in my Instagram of the bare board over a year ago. You can recognize it in the middle of 3 bare pc boards that I’m holding in one of the old pix.
Due to persistent medical problems, I have not yet fitted it into a box, though I did complete the pcb and prepare the enclosure. I hope to get it put together before long.
I have seen a number of similar designs recently based around the EHX Muff 2, and those circuits differ quite a lot from my old design. I believe that mine will sound more like a vintage Muff because of the way I carefully prepared each gain stage to duplicate the equivalent transistor stage.
I made a list of the most common parts that I use in pedals, and the drills and wrench sizes that are needed to install them.
I have sets of wrenches in both imperial and metric, but I need to order a set of metric drill bits. I have been using a couple of step drills but they are not exact fits, and are frankly a bit difficult to use when they get clogged with aluminum.
I also have a set of Rocket Sockets but I am afraid to put much torque on them because they might strip out or break.
I hope you find a use for the list and if you think of any parts that should be added to it, let me know.
from my Instagram post
I set up a breadboard in order to conduct tests on diodes to compare clipping harmonics. The idea is to see if there is really a difference between different types of silicon diodes when used as clippers.
I adjusted the test rig to drive the diodes to 10% distortion to make the comparison. While adjusting the setup, I noticed that after 5 to 10 seconds, the percentage of distortion would slowly go down. The change was very slow but noticeable. I repeated the adjustments several times with the same results. It then struck me that maybe the diodes were heating up and the forward voltage was changing ever so slightly as they warmed.
I started the oscillator and waited for the diodes to begin the slow change. Once the steady decline started, I blew on the diodes to cool then off. Sure enough, the distortion change stopped then slowly reversed! Once I stopped blowing on them, the slow decline began again.
The change I was looking at was very slight but easily seen since I was looking at the distortion percentage down to 3 decimal places. I doubt the change would be audible but it is interesting to note that the effect is definitely there.
In the end, I got around it by sending a short burst of the test signal and measuring the distortion before the diodes had a chance to heat up.
I have been working on an updated version of the gyrator bandpass filter calculator that has a chart with instant updating!
After more than 16 revisions, I am getting closer to something that I like, and which I think will be useful. Just for readers of this blog, you can try out the beta version at:
http://www.muzique.com/lab/gyrator2.htm
This probably a temporary link so don’t bookmark it yet. The intro paragraph with schematic is not on the page yet but I will put it back once I get to the final release.
I am working on a new issue of Analog Music Projects. The last one came out 24 years ago, so it is time for another one. Actually I had it all completed but when compiling the table of contents, it did not look like there was enough good information. So I have gone back into writing and will add a few more sections.
The good news is that the third issue (v1.3) already has some articles ready so maybe I can get out a follow-up in less than 24 years!!!
Update: This edition is finished but not yet formatted for final output. I am terribly slow, but there is a good reason for it that I will explain in the near future.
TL;DR: The pedal is not working correctly. I suspect it is a wiring error on my part and I am looking for it.
Full Story: I went to test the new pcb for the SSM2166 compressor pedal. The laptop on my test bench had not been used in several months, and Windows had updated. It now was forcing me to log into a Microsoft account and use OneDrive. I don’t need OneDrive and I don’t need a Microsoft account for this computer that is only used for testing and audio recording. Not only that, I did not remember the password for that laptop’s account. But, I had written it down, and after a lengthy search, I found the password and got in.
Next came a succession of errors on my part related to cables and jacks that were not labeled. Once I got that sorted, and all the cables plugged in correctly, I could run a few tests. The pedal did not work correctly. It worked in bypass but not when compressing. That sounds like a wiring error but this is a buffered bypass pedal so I would not expect it to work if the bypass wiring was wrong. But it did.
I looked closely at the switch wiring. It was correct. I suspected the battery but it was lighting the LED to full brightness. I tested 2 other pedals that were on the bench and they worked as expected (on the same battery).
Back to looking more closely at the inside of the comp pedal. Then it struck me… the 3pdt switch was oriented correctly for true bypass, but turned 90 degrees for a buffered bypass. Doh!
I pulled all the wires off the switch and turned it around. All of the switch lugs were plugged with solder so the wires would not go back in without a fight. Blah, blah, blah… I finally got it wired up.
So after some tests, it passes a signal on bypass but not a good one. It is losing some volume. At this point, I have to take a break. It is hot in that room and I am sweating, and I have looked at the wiring too long. Later, after resting my eyes, I’ll have another look at it. I may have damaged the op amp when moving cables and wires.
4/27 Update: I was right in that fresh eyes would be able to spot the problem. It only took me about 2 minutes to find the misplaced wire in the prototype’s ratsnest. The good news is that voltages are perfect and the buffered bypass is clean and stable. The bad news is that it does not compress properly. I was afraid of that because I went WAY off the datasheet’s basic design on this version and it looks like that was a bad idea because the internals of the chip were not doing what I thought they did. I still have to test the ssm2166 chip to make sure it is functioning properly but I expect it to be okay.
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Jack Orman has been involved in FX design and construction since the mid-1970s.
